The broadcast was carried on Channel 4 as an alternative to the Queen's traditional Christmas message.

Mr Snowden focused on privacy, saying: "A child born today will grow up with no conception of privacy at all."

The 30-year-old has temporary asylum in Russia after leaking details of US electronic surveillance programmes.

'Mission accomplished'

Mr Snowden opened his two-minute message, recorded in Russia, with a reference to novelist George Orwell, author of 1984, saying the surveillance technology described in his works was "nothing compared to what we have today".

How intelligence is gatheredAccessing internet company dataTapping fibre optic cablesEavesdropping on phonesTargeted spying

He said: "A child born today will grow up with no conception of privacy at all. They'll never know what it means to have a private moment to themselves, an unrecorded, unanalysed thought.

"The conversation occurring today will determine the amount of trust we can place both in the technology that surrounds us and the government that regulates it.

"Together we can find a better balance, end mass surveillance and remind the government that if it really wants to know how we feel, asking is always cheaper than spying."